1. Field of the Invention
The present invention relates to a gas turbine engine in the aviation field and relates to the installation of a shaft inside the engine, more particularly the upstream end of the high pressure compressor shaft in a double-bodied engine.
2. Description of the Related Art
The operations for installing and removing turbo engines are awkward due to the number of parts which they comprise and the small clearances therebetween, whilst the dimensions may be considerable. The cost of working on engines of this type is, as a result, always high. The aim, therefore, is continually to simplify them. In a front, double-bodied turbofan engine, such as the cfm56 engine, the access to the bearing supporting the high pressure compressor shaft is particularly difficult as it is installed in the region of the intermediate casing behind the fan and the first two bearings supporting respectively the low pressure compressor shaft and that of the fan.
It will be recalled that the term: “intermediate casing” denotes the element of the structural stator behind the casing of the fan through which passes a portion of the forces between the engine and the aircraft and which supports the front bearings of the rotors. The intermediate casing comprises a hub designed to support the bearings including the front bearing of the shaft of the high pressure rotor. The hub is connected to an external ferrule by radial arms which pass through the primary and secondary flows. The bearing of the HP compressor supports in rotation the front end of the HP compressor shaft. In front of this shaft, in its axial extension, is mounted a bevel pinion which meshes with a bevel pinion integral with a radial shaft. These pinions together form the IGB (intermediate gear box). The radial shaft drives at its radial external end, on the casing of the fan, the gears of the gear box, denoted AGB (accessories gear box), for mechanically driving the auxiliary equipment of the engine: pumps, electrical current generators or the like.
In order to avoid dismantling the whole front part of the engine and the fan in particular, the elements of the bearing are designed so as to allow installation from the rear. Such a solution is advantageous but requires care.
One known solution on a double-bodied turbofan engine uses a complex system, comprising numerous parts, which is difficult to manufacture and to install. This solution requires, moreover, a considerable length of time for its installation which is not compatible with small-sized engines.
Moreover, this known solution is not compatible with a centrifugal scoop system of lubrication.